1. Field of the Invention
The invention relates to an apparatus for recording a first and a second digital information signal in slant tracks on a magnetic record carrier, the apparatus comprising
input means for receiving the first and second digital information signals,
signals processing means for processing the first and second digital signal into first and second trick play signals respectively, suitable for recording in the tracks,
writing means for writing, at a recording speed of the tracks on the record carrier the first and second trick play signals so as to obtain trick play segments located at specific positions in said tracks, the first digital information signal being meant for enabling a replay in a reproduction apparatus at a trick play reproduction speed which equals n1 times the recording speed, the second digital information signal being meant for enabling a replay in said reproduction apparatus at a trick play reproduction speed which equals xe2x88x92n1 times the recording speed, where n1 is an integer unequal to 0 and 1.
2. Description of the Related Art
Such a recording apparatus is known from U.S. Pat. No. 5,751,889, corresponding to WO 95/28061, document D4 in the list of related documents. The known apparatus takes the form of a digital video recorder for recording a digital video signal. The digital video signal may be in the form of an MPEG-encoded video signal, in which packets of information of the digital video signal are included in the serial data stream of the MPEG-encoded video signal. In addition to such MPEG-encoded video signal, a trick play signal can be recorded in the tracks on the record carrier. Such trick play signal can be the same video signal, but reproduced at a record carrier (trick play) speed which is other than the nominal reproduction speed. Generally, a separate datastream is recorded the trick play signal on the record carrier for enabling the reproduction at such trick play speed. The trick play signal can be derived from the MPEG-encoded video signal, e.g., by selecting I-frames from the MPEG-encoded video signal.
This trick play signal, however, need not necessarily be a trick play signal that has a relationship with the MPEG-encoded video signal, but can be a completely different signal. But, in the same way as the MPEG-encoded digital video signal, the serial datasteam of the trick play signal comprises packets of information of the trick play signal.
The document mentioned above describes the recording of segments of information of a plurality of trick play signals in the tracks on a record carrier. The segments of a specific trick play signal have a specific position in the tracks in order to enable reproduction of the trick play signal at its corresponding trick play reproduction speed.
It is an object of the invention to provide an improved recording apparatus for recording a plurality of trick play signals in accordance with a specific format on the record carrier, such that a trick play reproduction in a forward or a reverse direction is possible.
The recording apparatus in accordance with the invention is characterized in that the first and second trick play signals comprise sync blocks of information of the first and second digital information signals, respectively, and that the writing means are adapted to write the sync blocks of the first trick play signal into a plurality of first trick play segments and to write the sync blocks of the second trick play signal into a plurality of second trick play segments, so as to enable, during reproduction at said trick play speed n1 times the recording speed in said reproduction apparatus, which is provided with reading means for reading the first and second trick play segments, said reading means comprising a rotatable head drum on which one or more read heads are located, the reading of ml sync blocks of the first trick play signal from said plurality of first trick play segments during one revolution of the head drum, and so as to enable, during reproduction at said trick play speed xe2x88x92n1 times the recording speed, the reading of m1 sync blocks of the second trick play signal from said plurality of second trick play segments during one revolution of the rotatable head drum, where m1 is an integer larger than 1, and that the trick play sync blocks comprise a sync word portion, an identifier portion, a header portion and a data portion, the header portion comprising a trick play direction identifier, said direction identifier identifying whether a trick play sync block meant for a specific trick play speed is meant for said trick play speed in the forward or in the reverse direction.
With this measure, it is possible to identify trick play sync blocks for a certain trick play speed from trick play sync blocks recorded for the same trick play speed, but in the other direction.
It should be noted, in this respect, that in earlier proposals, the trick play signals for trick play speeds in the forward direction were read by one or more read heads having one and the same azimuth angle, whereas, the trick play signals for trick play speeds in the backwards direction were read by one or more read heads having one and the same azimuth angle, which is different from the first mentioned azimuth angle. Therefore, there was no need to have a specific identifier for identifying the diction of the trick play speed. In a speed lock mode, the record carrier is transported in such a way past the rotating head drum that the head or read heads having the first mentioned azimuth angle scan the trick play segments for the trick play speed in the one direction, whereas the trick play segments for the other direction cannot be read by the read head or heads, because of the differing azimuth angles. Therefore, there was no need to use a direction identifier. In accordance with the present invention, read heads of both azimuth angles are used for reproduction at any of the trick play speeds. Therefore, it is required to add a direction identifier in order to discriminate between the sync blocks for the forward and the backwards direction.